or THE VOMEE, ETHMOID, AND INTEEMAXELLAEY BONES. 
301 
anterior extremity it presents two processes ; one passing into the anterior palatine canal, 
the other inclined somewhat upwards behind the surfaces of contact of the intermaxil- 
laries. The superior and inferior margins of the vomer are thus rendered continuous 
with those of the intermaxillaries. 
In the two-horned species of Ehinoceros the intermaxillaries are very small, and con- 
sist merely of lateral plates, without vestige of mesial-palatine processes ; while the 
anterior extremity of the vomer stops short on the palate plates of the maxillaries, some 
distance behind their anterior margin. But in Mhinoceros indicus (which unfortunately 
I have not examined) a process of considerable size is described as arising from behind 
the superior margin of the intermaxillary ; and in M. tichorhinus, not only is the osseous 
septum of the nose rendered complete by this process reaching up to the nasal bone, 
but the thick nasals are prolonged downwards to the level of the palate, and articulate 
with the anterior extremities of the intermaxillaries, so as to form a complete arch of 
bone in front of the nostrils, the only instance of this among Mammals*. 
In the Tapir we have another instance of intermaxillaries without any mesial-palatine 
processes, and the anterior extremity of the vomer stopping short upon the maxillary 
bones ; the intermaxillaries, however, are of considerable size, and come in contact with 
one another for a considerable distance in front of and above the septal cartilage, exactly 
as in the case of the Horse, only much more extensively (fig. 20). 
Eodentia . — In the Eodentia the vomer is remarkable for the very little tendency it 
evinces to articulate with the maxillaries. Its superior connexions are typical, i. e. it is 
continuous with the lateral masses of the ethmoid, and the margin of junction of the 
ethmoid and ethmovomerine lamina enters into the formation of the nasal foramen of 
the palate bone, as seen from within. In all those that I have examined the vomer is 
bifid in front, and fits on edge to edge with those parts of the mesial processes of the 
intermaxillaries which bound the groove for the septal cartilage. The mesial processes 
of the intermaxillaries are well developed, and are expanded laterally in connexion with 
Jacobson’s organs in a very characteristic fashion. The edges for articulation with the 
vomer are sometimes, as for instance in the Hare, very minute : but in other species with 
strong incisors they are well developed ; thus they are of considerable size in the Paca 
(fig. 21) ; while in the Porcupine they are remarkably elevated, and the vomer sends 
down a process from its mesial plate between them. 
In the Eat, the Beaver, the Porcupine, and the Paca, the vomer comes in contact with 
the anterior extremity of the maxillary part of the palate plate by a little, slightly dilated 
point ; in the Squirrel it scarcely comes in contact. But the most interesting condition 
is seen in the Hare and Eabbit : they have only one single large foramen incisivum ; for 
although the mesial-palatine processes of the intermaxillaries project well backwards, the 
palate plates of the maxillaries do not come far enough forwards to meet them : the vomer 
does not even approach the maxillaries, but its posterior margin terminates inferiorly in a 
thickened angle, which articulates with the intermaxillaries in such a manner as to be 
* CuTiEE, Ossemens Eossiles, tom. ii. Meckel, Anatomie Comparee (traduit), tom. iv. p. 273. 
